Public Interface IFormatter
    Function ApplyFormatting(ByVal text As String) As String
End Interface

Public Class GenericFormatter
    Implements IFormatter

    Public Function ApplyFormatting(ByVal text As String) As String Implements IFormatter.ApplyFormatting
        Return text
    End Function
End Class


Public Class TimeStampedFormatter
    Implements IFormatter

    Public Function ApplyFormatting(ByVal text As String) As String Implements IFormatter.ApplyFormatting
        Return String.Format("{0}: {1}", DateTime.Now, text)
    End Function
End Class